Genetic diversity in bread wheat as revealed by rapd markers and its relationship to leaf rust and hybrid performance
2010
El-Maghraby, M.A. | El-Shehawi, A.M. | Harby, M.H.
Random Amplified Polymorphic DNA (RAPD) technique was used as a tool to determine the combining ability and heterosis among six-parental diallel cross of common Egyptian wheat. Analysis of variance of yield detected highly significant differences among the progenies. General combining ability (GCA) and Specific combining ability (SCA) were successfully used to determine the differences among the crosses. Three Egyptian wheat cultivars were highly susceptible to leaf rust, while the other three were resistant (monogenic lines carrying different Lr genes). Crosses revealed resistant to leaf rust were derived from the cross between resistant x resistant (Lr37, 38, and 39) and between resistant x susceptible (Sakha 8 x Lr37, and Sakha 93 x Lr37). Nei's genetic distance ranged from 0.73 to 0.87 among the four genotypes selected based on their reaction to leaf rust. The correlation of Nei's genetic distance with SCA for grain yield and heterosis ranged from 0.62 to 0.89. These results indicated that the level of SCA and heterosis depends on the level of genetic diversity between wheat genotypes examined. RAPD technique was effective in detecting a markers (OPO-08353) that is linked to some effective genes for affecting leaf rust (Lr37, 38, and 39) under Egyptian condition that could be used as a maker to screen the materials in segregating populations.
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